Spondylolisthesis is a condition in which a bone, typically a vertebra in the lower part of the spine, slips out of alignment with the bone below it. While adjacent vertebrae are normally aligned vertically, this slip results in the anterior portion of the superior vertebra to protrude in the anterior direction farther than the anterior portion of the inferior vertebra. If left untreated spondylolisthesis can cause pain in the lower back and legs. Spinal fusion surgery can be performed to treat the condition and relieve pain.
Spinal fusion is a procedure that involves joining two or more adjacent vertebrae with a bone fixation device to restrict movement of the vertebra with respect to one another. Spinal fixation devices are used in spine surgery to align, stabilize and/or fix a desired relationship between adjacent vertebral bodies. Such devices typically include a spinal rod, such as, for example, a relatively rigid fixation rod or a dynamic or flexible spinal rod, etc. (collectively referred to herein as a spinal rod), that is coupled to adjacent vertebrae by attaching the spinal rod to various bone fixation elements, such as, for example, hooks, bolts, wires, screws, etc. (collectively referred to herein as a bone anchor). Surgeons may commonly choose to install multiple bone anchors, as well as multiple spinal rods, to treat a given spinal disorder. In addition, surgeons may choose to incorporate one or more clamps to interconnect a spinal rod and bone anchor.
Traditionally, surgical techniques for spinal fusion have required the use of multiple instruments, each of which may require the use of more than one hand to operate. Thus, multiple surgeons may be required to manipulate the instruments required to perform a spinal fusion surgery. Also a number of bone anchor extension members of various shapes and sizes may be used to assist in the attachment of a clamp to the bone anchor. This results in a number of different instruments being required for each corresponding spinal fixation device or bone anchor extension member.